A study of energy transfer processes in zinc–porphyrin films using Monte Carlo simulation of fluorescence decay

Energy transfer in thin films of zinc tetra(-octylphenyl)-porphyrin (ZnTOPP) doped with the copper (CuTOPP) or free-base (H2TOPP) analogues were investigated by time-resolved fluorescence and Monte Carlo simulations, applied to a single domain model of parallel porphyrin stacks. Rate constants for intra- and inter-stack energy transfer are (0.8–1.1)×1012 and (71–91)×109 s−1, respectively. The fluorescence lifetimes for ZnTOPP and H2TOPP films are (1.80–1.88)×10−9 and (6.8–7.3)×10−9 s. The rate constant for H2TOPP to ZnTOPP back transfer is (8.8–9.4)×106 s−1. The results agree with those of a previous analytical analysis [1].